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The exercises described here conveniently exploit the built-in acceleration sensors in smartphones, devices that are becoming ubiquitous if not essential items for most students. This allows each student to have the opportunity for a hands-on experience and to collect their own data, reduces preparation time, and greatly reduces cost by removing the need of purchasing a gravimeter to perform the same or similar tasks in gravity surveys. These exercises further demonstrate the educational value of using smartphones as scientific tools and that freely available accelerometer software applications operate with acceptable tolerance. The differences between accelerometers placed in smartphones and gravimeters are further discussed in the companion paper, “Part 1: Smartphone Applications for Gravitational Acceleration Surveys.”

Geodesy is a very active and essential research discipline in geophysics but it is not a commonly studied subject at the secondary school or junior post-secondary levels. Far more frequently, gravity and gravitational acceleration are discussed, to some extent, in elementary kinematics or classical mechanics courses. This often takes the form of the force acting on a body or bodies due to gravity, or that the acceleration (agrav) of a free-falling body is 9.8(1) m/s2—which implies the setting of the question is at Earth’s surface. While the latter is a reasonable and practical approximation, agrav observed over the surface of Earth varies and is dependent on several factors. These are normally related to elevation and latitude variations caused by Earth’s rotation. Earth’s rotation contributes negatively to agrav at the equator due to the centrifugal force outward and equatorial bulge, which makes the equatorial radius larger than the polar radius. Offsetting this partially is the positive contribution to agrav at the equator caused by the equatorial bulge because of the extra mass comprising the bulge.

The isostructural dimers of the 1,4-phenylene-bridged bis-1,2,3,5-dithia- and bis-1,2,3,5-diselenadiazolyl diradicals 1,4-S/Se are small band gap semiconductors. The response of their molecular and solid state electronic structures to pressure has been explored over the range 0-10 GPa. The crystal structures, which consist of cofacially aligned (pancake) π-dimers packed into herringbone arrays, experience a continuous, near-isotropic compression. While the intramolecular covalent E-E (E = S/Se) bonds remain relatively unchanged with pressurization, the intradimer E···E separations are significantly shortened. Molecular and band electronic structure calculations using density functional theory methods indicate that compression of the π-dimers leads to a widening of the gap Δ E between the highest occupied and lowest unoccupied molecular orbitals of the dimer, an effect that offsets the expected decrease in the valence-to-conduction band gap E

Magnetism is traditionally taught within the subject of electromagnetism at the undergraduate and graduate levels in physics courses, with the goal of establishing a solid foundation of the underlying physical mechanisms before advancing to more specialized topics. Oftentimes, a laboratory component of these courses involves practical, hands-on exercises that include, e.g., characterization of magnetic properties of materials and dipoles, measuring the vertical and horizontal component of a magnetic field generated by power supplies, or measuring the EMF induced in a wire coil due to a changing magnetic field. Here, we provide a complement to these activities with a discovery exercise akin to an outdoor magnetic field survey, one that leverages the ready availability of strong small rare earth magnets (“neo-magnets”).

The electrical resistivity of gold was experimentally measured at high pressures from 2 to 5 GPa and temperatures ∼300 K above melting. The resistivity decreased as a function of pressure and incre...

The Earth's core is comprised mainly of Fe and Ni with some light alloying element(s) and the electrical resistivity behavior of these elements is an important property for characterizing geodynamo action, determining energy sources, and for understanding core thermal evolution. Knowledge of the electrical resistivity of solid and liquid transition metals with electronic structures similar to Fe reinforces our understanding of core properties. The electrical resistivity of high purity Co has been measured at pressures up to 5 GPa in a large volume press and at temperatures up to 100 K above the melting temperature. The results demonstrate that resistivity of Co is invariant along the melting boundary. This is interpreted in terms of the antagonistic effects of P-induced reduction in the amplitude of lattice vibrations tending to decrease resistivity, and the P-induced shift of the Fermi level closer to the d-resonance which tends to increase resistivity. We calculated the electronic thermal conductivity of Co using the Wiedemann–Franz law and show that it increases with pressure both in the solid and liquid states and decreases with temperature in the solid and increases in the liquid state. The pressure dependences of electrical resistivity and electronic thermal conductivity calculated from equations involving bulk modulus and the Gruneisen parameter are in reasonable agreement with values measured in this study. The constant resistivity of Co along its melting boundary found in our study portends similar behavior for its electronic structural analog, Fe. This prediction suggests that the electronic thermal conductivity of Fe at Earth's inner core boundary could be similar to its 1 atm value at the melting point. Using this value of thermal conductivity for the inner core boundary would admit thermal convection as an energy source for the geodynamo prior to the birth of the inner core.

Characterization of transport properties of liquid Ni at high pressures has important geophysical implications for terrestrial planetary interiors, because Ni is a close electronic analogue of Fe and it is also integral to Earth's core. We report measurements of the electrical resistivity of solid and liquid Ni at pressures 3–9 GPa using a 3000-ton multi-anvil large volume press. A 4-wire method, in conjunction with a rapid acquisition meter and polarity switch, was used to overcome experimental challenges such as melt containment and maintaining sample geometry, and to mitigate the extreme reactivity/solubility of liquid Ni with most thermocouple and electrode materials. Thermal conductivity is calculated using the Wiedemann-Franz law. Electrical resistivity of solid Ni exhibits the expected P dependence and is consistent with earlier experimental values. Within experimental uncertainties, our results indicate that resistivity of liquid Ni remains invariant along the P-dependent melting boundary, which is in disagreement with earlier prediction for liquid transition metals. The potential reasons for such behaviour are examined qualitatively through the impact of P-independent local short range ordering on electron mean free path and the possibility of constant Fermi surface at the onset of Ni melting. Correlation among metals obeying the Kadowaki-Woods ratio and the group of late transition metals with unfilled d-electron band displaying anomalously shallow melting curves, suggest that on the melting boundary, Fe may exhibit the same resistivity behaviour as Ni. This could have important implications for the heat flow in the Earth's core.

We measured the electrical resistivity of high purity Zn along the melting boundary, up to 5 GPa in a large volume press. The electrical resistivity remained constant on the melting boundary, as predicted in a thermodynamics-based model for simple metals. The effects of pressure and temperature on the electrical resistivity of the solid and liquid states are interpreted in terms of their antagonistic effects on the electronic structure of Zn. Within the error of measurements, our melting temperature data agree well with those of the previous studies. The electronic thermal conductivity was calculated from resistivity data using the Wiedemann–Franz law and shows a decrease with temperature in the solid state and an increase in the liquid state, with a large decrease on melting. Comparison of calculated electronic and measured total thermal conductivities indicates that the electronic component dominates over the phonon component in Zn.

O 1s X-ray Photoelectron Spectroscopic (XPS) results for K-silicate glasses near the K-disilicate composition indicate the presence of at least two, and likely three, types of Bridging Oxygen (BO), which are distinguished by the number of K ions coordinated to BO (BO-K moieites). The relative abundances of these moieties cannot be accurately determined from XPS spectra, but based on crystalline K-disilicate, they are likely to be BO, BO-K 1 and BO-K 2 or BO-K 1 , BO-K 2 and BO-K 3 (subscript indicates the number of K + coordinated to BO). The presence of three BO moieties is consistent with crystallographic results for crystalline K-disilicate (K 2 Si 2 SiO 5 ) and their presence in K-silicate glass may be assessed using high quality molecular dynamics studies. The binding energy (BE) separating each BO-K peak is ~ 40 to ~ 70 kJ and sufficient to affect stretching frequencies in Raman and IR spectra, and to effect the electronic properties of O and Si atoms in 17 O and 29 Si NMR spectra. The BO moieties may give rise to separate signals or they may coalesce to produce a broad, asymmetric band in Raman, 29 Si NMR and 17 O NMR spectra, just as they do in O 1s XPS spectra. The O 1s XPS and previously published 17 O NMR spectra of glasses containing ~ 20 and ~ 35 mol% K 2 O are well resolved. Both types of spectra yield the same NBO and BO abundances within experimental uncertainty. For 20 mol% K 2 O glass, the O 1s XPS results yield ~ 21.5 mol% NBO and ~ 78.5% BO whereas the 17 O MAS NMR results are ~ 22.2% NBO and 77.8% BO. The 35 mol% K 2 O glass yields similarly close agreement between O 1s XPS and 17 O MAS NMR spectral fits. Both techniques can provide accurate oxygen species abundances provided the spectra are of high resolution, and provided complete fits are performed on the spectra. A 2D 29 Si MAF NMR spectrum of K-disilicate glass indicates that two Q 4 contributions are present in the spectrum, as previously observed in highly siliceous K-silicate glasses. One explanation for two peaks is that one Q 4 signal represents Q 4 tetrahedra attached to Q 3 tetrahedra and the second peak represents Q 4 attached to other Q 4 species. An alternative explanation is offered based on these findings. The two Q 4 signals may result from different types of BO-K moieties bonded to Si centers of Q 4 species. K + , located in the second coordination sphere of BO, modifies the electronic (valence band) properties of the BO and Si atoms of the tetrahedron, thereby producing two Q 4 signals. The 2D 29 Si MAF NMR, 17 O NMR and O 1s XPS spectra indicate ~ 2 (± 1) mol% O 2 − in the K-disilicate glass. These three types of spectra yield remarkably similar results when high resolution spectra are collected and complete fitting of the spectra are performed.

The Wiedemann-Franz Law is often used to calculate the thermal conductivity of Fe from experimental measurements of the electrical conductivity. It is shown by measurements of the Seebeck coefficient (S) of solid and liquid Fe at pressures up to 6 GPa and temperatures up to 2100 K that the Sommerfeld value ( L 0 = 2.445 × 10 −8 W Ω K −2 ) of the Lorenz number ( L ) represents more than 99% of the electronic component of the thermal conductivity of Fe. Using experimental values of electrical resistivity and thermal conductivity of Fe, L / L 0 is shown to vary by as much as 1.22 in the solid state and 1.32 in the liquid state, signifying a non-negligible phonon component. An expression for the pressure dependence of L at the melting boundary up to 5 GPa is derived for electron-phonon scattering. For Fe-Si alloys, L / L 0 varies more than for pure Fe and generally increases with increasing Si and state of disorder. New values for the conductive heat flow in a pure Fe core of Mercury are presented.

At transition zone depths in subduction zones, deep-focus earthquakes (300–690 km depth) are thought to be associated with faulting that arises from phase transformations. In order to test the viability of this mechanism experimentally, an investigation was conducted on fayalite at high pressure, P, and high temperature, T, under deviatoric stress in order to initiate transformational faulting. Experiments were performed in a 3000-ton multi-anvil press using an 18/11 octahedral cell with 6 piezoelectric transducers mounted on the rear side of the anvils to monitor acoustic activity in situ. Acoustic emission (AE) signals were collected at a sampling rate of 40 MHz using a triggered system and a data buffer for capturing full waveforms of AE events. The use of multiple transducers distributed in a micro-seismic array allowed for events to be located within the sample based on the arrival time of signals and non-linear least squares inversion techniques. Uncertainty in location estimates were on the order of ~1 mm. The system was tested by comparing the contrasting mechanical properties of quartz beads and AgCl samples. The multi-anvil apparatus constitutes an inherently noisy environment both acoustically and electrically, therefore methods of noise reduction were developed. Results of AE experiments on Fe2SiO4 under high pressure (3.7–9.2 GPa) and high temperature (673–1273 K) conditions in the spinel stability field showed acoustic events that locate within or within 1σ of the sample in five experiments defined by the P,T envelope P = 3.9–8.4 GPa and T = 748–923 K. Optical and scanning electron microscopy of the recovered specimens displayed conjugated faulting associated with transition from fayalite (olivine structure) to ahrensite (spinel structure) and microstructural analysis revealed microstructural morphology identical to that found in similar faulting experiments on Mg2GeO4. This is the first time an olivine→spinel structured transition in a silicate mineral has demonstrated macroscopic faulting and associated microstructures, as well as acoustic activity, under conditions that nominally promote plastic deformation.

Pressure-induced changes in the solid-state structures and transport properties of three oxobenzene-bridged bisdithiazolyl radicals 2 (R = H, F, Ph) over the range 0–15 GPa are described. All three materials experience compression of their π-stacked architecture, be it (i) 1D ABABAB π-stack (R = Ph), (ii) quasi-1D slipped π-stack (R = H), or (iii) 2D brick-wall π-stack (R = F). While R = H undergoes two structural phase transitions, neither of R = F, Ph display any phase change. All three radicals order as spin-canted antiferromagnets, but spin-canted ordering is lost at pressures

A large body of work has focused on resistivity saturation in systems where scattering is caused by impurities or by thermal effects. Electrical resistivity saturation is here classified as either static, where impurity scattering causes saturation, or dynamic, where changing external parameters such as temperature or pressure cause saturation. Resistivity measurements up to 5 GPa show pressure-induced resistivity saturation in Fe17wt%Si by the change in sign from positive to negative of the temperature coefficient of resistivity. The pressure dependence of the Curie temperature is 10.2(8) K GPa−1. The Debye temperature is calculated from the Bloch–Gruneisen equation and yields a pressure dependence of 40(9) K GPa−1.

Malfait challenges our XPS results by arguing that the XPS spectroscopic technique cannot be used to determine small amounts of O2– in potassium silicate glasses. Instead, he claims that there is no free oxide (O2–) in potassium silicate glasses based primarily on his 29Si MAS NMR spectroscopic results. In this rebuttal, we demonstrate that O1s XPS and well-resolved 2D 29Si MAF NMR spectral results of potassium disilicate (K2Si2O5) glass are consistent with each other and that both techniques indicate the presence of a few mol% of O2– in the glass. Neither of these techniques, however, supports the interpretation of the 29Si MAS NMR results presented in the comments of Malfait. The major difficulty relates to the low resolution of the 29Si MAS NMR spectra, which does not reveal the Q4 signal beneath a strong Q3 peak in these spectra. The proof is provided by the 2D 29Si MAF NMR spectrum of potassium disilicate glass in which both Q3 and Q4 peaks are revealed; the 2D 29Si MAF NMR results for potassium disilicate glass are far more informative than 29Si MAS NMR spectra. It demonstrates that the potassium disilicate glass (K2Si2O5) contains greater Q4 intensity, is more polymerized than previously considered, and that O2– is present at ∼2 (±1) mol% in the potassic glass. This O2– value confirms our O1s XPS results. Specific points raised by Malfait are rebutted in Appendix A .

The heat capacity at constant pressure (CP) data of rutile and synthetic TiO2II were measured in the temperature range of 5–465 K using the heat capacity option of the physical property measurement system (PPMS) and by differential scanning calorimetry (DSC). The entropy values for rutile and TiO2II at standard temperature and pressure conditions calculated from the measured heat capacity data are 50.22 ± 0.20 and 47.50 ± 0.20 J mol−1 K−1, respectively. The CP for both phases were also calculated using the Kieffer model to extrapolate CP to higher temperatures beyond experimental range. These new thermodynamic data were used to calculate the phase transition boundary between rutile and TiO2II with the help of other parameters available in the literature. The calculated phase boundary is compared with previous experimental results and possible reasons for the differences are discussed.

The pressure-induced anomalously high AC conductivity of zeolite NaA mixed with water was measured by impedance spectroscopy at various water/zeolite ratios. The conductivity reaches a maximum value at 0.9–1.4 GPa with increasing water content of up to 20 wt.% in NaA + water. The high ionic conductivity of NaA compressed in water is interpreted to result from cation diffusion in the quasi-liquid Na+–H2O intra-channel system enhanced by the filling of additional H2O sites. The pressure range of anomalously high AC conductivity in NaA enlarges towards higher pressures with decrease of the water/zeolite ratio. An abrupt drop in conductivity observed at P > 1.5 GPa appears to be associated with freezing of intra-channel water. After pressure release, the overhydrated state of the zeolite kept in a closed container can be preserved for a long time, providing abnormally high conductivity which is comparable with that of Na+ β-alumina.

We have measured liquid Fe metal–liquid silicate partitioning (Di) of tellurium, selenium, and sulfur over a range of pressure, temperature, and oxygen fugacity (1–19 GPa, 2023–2693 K, fO2 −0.4 to −5.5 log units relative to the iron-wustite buffer) to better assess the role of metallic melts in fractionating these elements during mantle melting and early Earth evolution. We find that metal-silicate partitioning of all three elements decreases with falling FeO activity in the silicate melt, and that the addition of 5–10 wt% S in the metal phase results in a 3-fold enhancement of both DTe and DSe. In general, Te, Se, and S all become more siderophile with increasing pressure, and less siderophile with increasing temperature, in agreement with previous work. In all sulfur-bearing experiments, DTe is greater than DSe or DS, with the latter two being similar over a range of P and T. Parameterized results are used to estimate metal-silicate partitioning at the base of a magma ocean which deepens as accretion progresses, with the equilibration temperature fixed at the peridotite liquidus. We show that during accretion, Te behaves like a highly siderophile element, with expected core/mantle partitioning of >105, in contrast to the observed core/mantle ratio of ∼100. Less extreme differences are observed for Se and S, which yielded core/mantle partitioning 100- to 10 times higher, respectively, than the observed value. Addition of ∼0.5 wt% of a meteorite component (H, EH or EL ordinary chondrite) is sufficient to raise mantle abundances to their current level and erase the original interelement fractionation of metal-silicate equilibrium.

Equation of state (EOS) of liquid Fe–17 wt%Si has been investigated at a temperature of 1773 K and pressures up to 12 GPa by the sink/float technique using composite spheres. The EOS of liquid Fe–17 wt%Si, in the form of the second order Birch–Murnaghan equation, produces K 0T=68±2 GPa when K′0T=4.0. Considering the effect of temperature and pressure on K 0T, extrapolation of this EOS to Earth's outer core conditions reveals that the addition of Si to liquid Fe decreases its density ρ and increases its compressional wave velocity V P , indicating that Si is a possible light element candidate in the outer core. The possible existence of Si in the cores of other planetary bodies is also discussed.

Hydrated and dehydrated zeolites MA (where M=Li, Na and K) with LTA structure have been studied by impedance spectroscopy with scanning frequency from 1 Hz to 1 MHz at high pressure up to 4.5 GPa and high temperature up to 250 °C. Anomalous increase in electrical AC conductivity at about 1.5–2 GPa observed in hydrated zeolites is associated with changes in crystalline structure leading to the formation of high-diffusion state of cation and water stuffing of the channels. In dehydrated zeolites, electrical conductivity is controlled by diffusion of cations (Li + , Na + and K + ), which is determined by cation sites and aluminosilicate ring windows. LiA and NaA zeolites show normal decrease of conductivity with pressure, whereas KA zeolite exhibits the anomalous dependence with considerable increase and then fast decrease of conductivity. The behaviour of KA zeolite is associated with nearly central location of cation site in 8-membered ring, different from that in LiA and NaA zeolites.

Hydrated NaA (hyd-NaA) and dehydrated NaA (deh-NaA) zeolites were studied at high P–T conditions (up to 4.5 GPa and 400 °C) by ex situ X-ray powder diffraction and in situ impedance spectroscopy. A...

Measurements of the change in heat (enthalpy) of solid–solid transition ΔHt and of fusion ΔHfus in crystalline CsCl effected by the presence of guest ion K+ up to 56.5 mol% using differential scanning calorimetry are reported. The range of K+ solubility is found to be higher and at variance with the subsolidus region described in earlier reports. Novel features of ΔHt and ΔHfus dependence on solute composition are in contrast to parallel binary systems, viz. CsNO3–RbNO3, CsNO3–TlNO3 and RbNO3–TlNO3. Some fundamental solution quantities are calculated from heat of transition, viz. slope ΔHt/x or Δ H solute and χ-apparent partial molar heat of solution and partial molar heat of solution at infinite dilution, respectively.

The adsorption of three ( p -, m -, o -) xylene isomers inside zeolite Y with different charge balancing cations including Na + , K + , Ba 2+ was studied by FT-Raman spectroscopy. Our Raman data indicate the formation of a π-complex between the xylene and cation as evidenced by observing the weakening of the C–C bonds in the aromatic ring. The strong interaction between a sorbate and a cation results in that the methyl groups of xylene are forced to interact with the local zeolite framework, namely, the six-membered ring that plays host to the cation, leading to an increase in vibrational frequency of methyl groups, upon adsorption. For a given cation, no significant differences were observed for the strength of interaction with any of the three isomers at a loading of 1 molecule per supercage.

Electrical conduction and crystal structure of Al 2 (WO 4 ) 3 at 400 °C have been studied as a function of pressure up to 5.5 GPa using impedance methods and synchrotron radiation X-ray diffraction, respectively. AC impedance spectroscopy and DC polarization measurements reveal an ionic to electronic dominant transition in electrical conductivity at a pressure as low as 0.9 GPa. Conductivity increases with pressure and reaches a maximum at 4.0 GPa, where the conductivity value is 5 orders of magnitude greater than the 1 atm value. Upon decompression, the conductivity retains the maximum value until the sample is cooled at 0.5 GPa. The high pressure–temperature X-ray diffraction results show that the lattice parameters decrease as pressure increases and the crystal structure undergoes an orthorhombic to tetragonal-like transformation at a pressure ∼3.0 GPa. The change of conduction mechanism from ionic to electronic may be explained by means of pressure-induced valence change of W 6+ →W 5+ , which results in electron transfer between W 5+ –W 6+ sites at high pressure.

The IR spectra of siliceous zeolite Y were measured as a function of external pressure. The results indicate that the siliceous zeolite Y undergoes pressure-induced amorphization. This phase transformation seems to be driven by the severe distortion of double six-membered rings joining the adjacent sodalite cages to form the zeolitic lattice. Unlike hydrated zeolite NaY and structurally related zeolite NaA, the amorphization is irreversible due to the lack of hydrated charge balancing cations.

Measurements of the change in heat (enthalpy) of transition in crystalline CsCl effected by the presence of guest ions K+, Rb+, Tl+, Br−, I− using differential scanning calorimetry are reported. The nature of each mixed-ion solid, ‘mixed crystal’ or ‘crystalline solid solution’ is discussed. The limits of solubility of each guest ion are found to be consistent with the subsolidus region described in its respective phase diagram. The quantitative heat of transition values are used to calculate some fundamental solution quantities, viz. slope ΔHt/x or Δ H solute , χ, ΔHS0, ΔHL0—apparent partial molar heat of solution, partial molar heat of solution at infinite dilution, the heat of solution, recovered lattice energy, respectively.

From measurements of the decrease in the heat (enthalpy) of transition in the solid phase using differential scanning calorimetry, the apparent molar heats of solution, slope Δ H t / x , the partial molar heats of solution at infinite dilution, χ , and the heats of solution, Δ H s ° , of Tl + in CsNO 3 crystal and Cs + in TlNO 3 crystal and Rb + in CsNO 3 crystal and Cs + in RbNO 3 crystal along with their recovered lattice energies, Δ H L ° , are reported. Δ H s ° of Tl + and Rb + in CsNO 3 crystal are each found to be negligible or zero representing an ideal solid solution, i.e. Δ H mix =0. The complete phase diagrams of the TlNO 3 –CsNO 3 and RbNO 3 –CsNO 3 systems with details of the sub-solidus regions are included. The properties of Tl (1− x ) Cs x NO 3 and Rb (1− x ) Cs x NO 3 compositions are discussed in terms of a ‘mixed crystal’ or ‘crystalline solid solution’ in relation to parallel compositions of Tl (1− x ) Rb x NO 3 .

We describe a new modification of the sink/float method of determining the density of molten materials under high pressure, and apply it to liquid Fe-10wt%hS. The modification is based on the use of composite spheres made of a dense, metallic core and a sapphire or ruby mantle. Composite spheres permit tailored densities for use in a variety of liquid compositions. The inert mantle also prevents chemical reaction with molten metallic samples. The pressure dependence of the density of liquid Fe-10wt%S at 1773 K, determined by bracketing, using composite spheres, is compared with the equation of state of Fe-10wt%S obtained by Sanloup et al. (2000), using X-ray absorption.

Melting of Fe-17wt%Si has been investigated at temperatures up to 1600°C and pressures up to 5.5 GPa in a cubic anvil press. The melting temperature, TM, was identified with the discontinuity in temperature and pressure dependence of electrical resistance. Two types of electrode materials, Pt and Fe, were used and gave consistent melting results. TM increases with pressure from 1200°C at 1 atm to 1430°C at 5.5 GPa. dTM/dP decreases with pressure and reaches a value of zero at P∼5 GPa. Combined with the thermal profiles of the proto-Earth, the pressure independence of the melting boundary of Fe-17%Si at the highest pressures of this study suggests core formation began early in Earth accretion with a substantial liquid metal phase fraction between 30 Ma and 42 Ma.

From measurements of the decrease in the heat (enthalpy) of transition in the solid phase by differential scanning calorimetry, the partial molar heats of solution at infinite dilution, χ, and the heats of solution or substitution, ΔHs°, of Tl+ in RbNO3 crystal and Rb+ in TlNO3 crystal along with their recovered lattice energies, ΔHL°, are reported. The complete phase diagram of the TlNO3–RbNO3 system with details of the sub-solidus regions is reported. The properties of a “mixed crystal’' or “crystalline solid solution’' of Tl(1-x)RbxNO3, viz., structure, transition temperatures, melting temperature, etc., are presented and discussed.

Dehydrated, hydrated and superhydrated NaA zeolites have been studied by impedance spectroscopy with scanning frequency from 1 Hz to 1 MHz at high pressure up to 4.5 GPa. A considerable anomalous increase in electrical conductivity in the range of 0.5–1.1 GPa was observed in superhydrated NaA zeolite containing additional water in the channels. A very high mobility of ions in superhydrated zeolite may be associated with the liquid-like state of the water-cation stuffing of zeolite channels. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Viscosity measurements of Fe73S27 (wt%) liquid at pressures between 2.0 and 5.0 GPa and at temperatures in the range 1100–1300°C have been made using Stokes' method of rising spheres in conjunction with a newly developed electro-detection technique. The viscosities range from 43.6±7.0 Pa-s at 3.9 GPa and 1100°C to 1.6±0.5 Pa-s at 3.0 GPa and 1300°C. These high P viscosity values are three orders of magnitude higher than the 1 atm values and are tentatively attributed to the effects of S on the size of viscous flow units. From the T and P dependences of viscosity, activation energy and volume, respectively, have been determined. Activation energy decreases with increasing P, from 405±77 kJ/mol at 2.0 GPa to 240±72 kJ/mol at 5.0 GPa, and activation volume increases with increasing T, from 1.51±0.01 cm³/mol at 1100°C to 3.61±0.19 cm³/ at 1300°C.

Aluminum K-edge XANES spectra of high pressure and high temperature (4.4 GPa and 1575°C) glasses along the NaAlSi 2 O 6 (Jd) - NaAlSi 3 O 8 (Ab) join are reported using synchrotron radiation, and shown to provide direct experimental evidence for the pressure-induced coordination change of Al. Five- and six-fold coordinated Al ( [5] Al and [6] Al), characterized by Al K-edge positions at 1567.8 and 1568.7 eV, respectively, first appear in glass of composition Jd 60 Ab 40 and increase in proportion progressively with increasing Jd content. The end-member jadeite glass contains about 6% of each of [5] Al and [6] Al. The present direct measurements confirm literature suggestions for the important role of Al in controlling viscosity and diffusion in mantle melts.

A new method that allows real time determination of the velocity of a sphere moving through a liquid in high pressure Stokes’ viscometry studies is described. Our electro‐detection method relies on the electrical conductivity contrast between sphere and liquid. The method has been tested on a jadeite melt at pressures of 2.4 and 2.9 GPa and at temperatures of 1350 and 1450 °C, respectively, and yields viscosities (with an associated error of 25%) which are consistent with those determined by the quench and probe method.

Compressional wave velocity Vp has been measured in liquid iron in the temperature range 1823–1883 K and in the frequency range 5.4–11.8 MHz for the first time using ultrasonic interferometry. The value of Vp at the melting temperature is 3820±3 ms−1 which is comparable to previous measurements all using time-of-flight methods. The temperature derivative of velocity, dVp/dT, in this temperature range (−0.72±0.07 m s−1 K−1 ) and the lack of dispersion observed in this frequency range are in agreement with previous studies. Our calculated value of the relaxed (adiabatic) bulk modulus K0 at the melting temperature is 102 GPa. Estimate of the average longitudinal relaxation time τl indicates that the liquid iron is in a relaxed state in the present frequency range. Accurate measurement of attenuation is not yet possible with our present apparatus, but typical interferograms indicate a very low attenuation, which is qualitatively consistent with the prediction from viscoelastic theory and seismological determinations of attenuation of Earth's outer core.

An ultrasonic interferometer has been developed for measuring compressional wave velocity (VP) and attenuation (or conversely, quality factor QP) in molten Fe, Fe‐Ni, Fe‐Ni‐S, and Fe‐Ni‐Si alloys. Results for pure molten Fe are presented. A radio frequency (rf) induction technique is used for heating that allows a ±1 K temperature stability at 1973 K. The effects of the electromagnetic field interaction with the molten conductive metal are discussed in terms of applicability to VP and QP measurements. Considerations of acoustic impedance and thermal absorption are presented to discuss the high‐temperature use of polycrystalline Al2O3 buffer rods for velocity and attenuation measurements. Viscoelastic theories, when applied to pure molten Fe, predict an extremely small acoustic coefficient of attenuation. Suggestions are made to circumvent the experimental difficulties encountered in attenuation measurements.